Rotary compressor



Jan. 2, 11923. c. B. PETSCHE.

RorARY COMPRESSOR.

FILED Oc'r. 6. 1920.

Ml VE N TOR Patented ill-an 2, 3%23.

UNEFFEE TAT t an GUSTAV B. PETSCHIE, 0F YONKERS, NEW YORK.

RQ'IAR'Y COMPRESSOR.

Application filed October 6, 1920. Serial No. 415,143.

To all whom it may concern Be it known that I, GUSTAV B. Parsons, acitizen of the United States of America,

and resident of Yonkers, county of Westchester, State of New York, haveinvented a certain new and useful Improvement in R0- tary Compressors,of which the following is a true and exact description, reference beinghad to theraccompanying drawings, which form a'part thereof.

Myinvention relates to rotary compressors of the type in which therotary piston consists of an eccentric ring having an extension whichforms a partition between the admission'and discharge ports of the pump.The object of my invention is to construct pumps of this kind especiallysuitable to act as compressors at high speed, the terminal pressure ofwhich gases is a large multiple of the initial pressure. In this casethe volume discharged is only a small fraction of the initial volume andthe period during which the outlet is to be open is only a small part ofthe compression cycle. These conditions require a discharge valve whichopens and closes the port 'with great rapidity and positively. Furtherobjects of my invention are to. provide a positivel actuated valveoperating in connection with the admission port of 'the compressor andto close such port during the period when the piston is out of contactwith the wall of the cylinder at whichtime re-expansion of that part ofthe compressed substance, retained in the clearance space and notdischarged,-

takes place. These residual gases build up a pressure in the cylinderand would escape into the admission port ifit is not closed and thusinvolve a considerable loss in volu-- metric elliciency, a loss to whichother rotary compressors, not having such valves are subject- A stillfurther object is to provide the piston with an automatically operatingvalve for the release of excess pressure such as is apt to occur in acompressor. in which considerable oil is carried with the gas to becompressed and where the discharge valve is opened and closed positivelyanda further object is to provide for the actuation of the deliveryvalve from the driving shaft of the pump 'by means which will notinvolve the use of stufiing boxes.

The nature of my improvements will be best understood as described inconnection with the drawings in which they are illustrated, and in whichFigure l is a side elevation of a pump provided with my improvementstaken on the section line 1-1 of Fig. 2.

v Figure 2 is a sectional elevation on the line 22 of Fig. 1.

Fig. 3 is a sectional detail, and

Figure 4 is a sectional elevation showing the application of myinvention to an alternative construction of the pump.

A, A, indicate the pumpcylinders formed in the single casting andprovided with face plates A and A B indicates. the cylindrical wall ofthe cylinder cut away at B and B C, Figs. 1 and 2, is a cylindricalbearing centered at H. D is the admission port formed, as shown, throughthewall of, the cylindrical bearing C. E is the delivery port on theopposite side of the compressor. F is the driving shaft of the pump towhich is secured the eccentrics indicated at F, F, on which are locatedthe eccentric ring pistons G having extending from them the extensionsindicated at G and extending like the'piston from side wall to side wallof the pump chamber. H and extending from wall to wall oil-the hearingor valve chamber C. (in one side this rock lever carries an admissionvalve M and on the other side a sliding shoe J, both.

fitting to the bored face of chamber C. T indicates a port formedthrough the partition G and provided .with a valve T spring seated andcapable of opening under a determined pressure. N indicates acylindrical seat or hearing for a rotary valve formed on the outer sideof the port E and on this hearing works the rotary valve having aportion of its face depressed as indicated'at P. This valve is rotatedby the shaft 0 onwhich is secured the gear wheel Q, in engagement with agear wheel Q on the shaft F. Q indicates a tight casing enclosing thegearing to prevent escape of gases which casing should be well chargedwith oil.

Referring to Figure 4, it will he observed that the eccentric ringpiston Gr is here shown as provided with an extension S forming theslide working in the swivel block R, seated in a bearing CC. Theadmission port to the compressing cylinder is here shown at S as formedthrough the slide S and opening. into the compressing cylinder at S theport S hearing such relation to the wall of the swivel block R I, I, isa rock lever pivoted at and stuffing boxes are avoided b that it will beclosed during the period when the piston is out of contact with thewalls B of the cylinder. In other respects the construction of Fig. 4 issubstantially similar to that of Figs. 1 and 2.

In operation the piston rotates in the anti-clockwise directionindicated by the ar row in Fig. 1. The fluid to be compressed is drawnin through the port M and delivered through the port E which, however,remains closed by the rotary valve P until the fluid has been compressedtothe desired point at which point the port P in the valve P registerswith the port E and permits the escape of the compressed fluid into thereceiver. Obviously, the amount of compression given to the flui'd bythe compressor Wlll depend upon the location and length of the port P.The rotary valve or valves where compressors are used in pairs, asindicated in Fig. 2, is driven from the main shaft F through the ears Q,Q', encasing the gears, as shown, and provi ing oil in the gear case.While for a. very high ratio of compression a delivery valve rotatinginone direction as shown is practically necessary, an-osoillating rotaryvalve may obviously be used'where the ratio of cpmpression is not solarge.

It is important that such compressed fluid as may remain in thecompression side of the pump at'the end of its compression stroke shouldnot be permitted to escape back through the admission port and should beheld in the cylinder of the pump in admixture with th fresh charge offluid to be compressed. The loss of pressure in the way indicated isprevented by providin the admission port with a valve which wilI- closeit during the period when the piston leaves contact with the walls ofthe pump cylinder. In the construction of Fig. 1 this function isperformed by the valve M and in the construction of Fig. 4 the admissionport S is closed by the bearing face of the swivel block through whichthe slide moves.

While I have shown the valve .as actuated by gearing which rot-ates itin one direction only, it will be obvious that any actuating gearsordevices which will move it to open and close the port at proper, timeswill be in abroad sense the full equivalent for the illustratedconstruction.

Having now described my invention, what I claim as new and desire tosecure by. Letters Patent, is:

1. In a rotary compressor having a rotary eccentric ring piston providedwith an extension forming a division between the admission and dischargesides of the cylinder, a discharge port leading from the cylinder,

a port formed through the piston extension and a spring seated valve insaid port adapted to open the port under excessive pressure.

2. In a rotary compressor having a rotary eccentric ring piston providedwith an extension formlng a division between the 311- mission anddischarge sides of the cylinder,

a bearing in the form of a cylindrical segment, a rock lever pivoted atthe center of the bearing,.a shoe on one end of the rock lever and asliding admission valve on the other end, said rock lever beingoperatively connected to the piston extension, a discharge ort leadingfrom the cylinder, a rotary va ve for opening and closing the dischargeport located at the outer end of said port, means operatively connectingsaid valve to the driving shaft of the compressorand a tightcasingenclosin said means.

GUSTAV 1%. PETSCHE.

